Spin-labeled small unilamellar vesicles with the T1-sensitive saturation-recovery EPR display as an oxygen sensitive analyte for measurement of cellular respiration. Appl Magn Reson 2015 Aug 01;46(8):885-895
Date
10/07/2015Pubmed ID
26441482Pubmed Central ID
PMC4591545DOI
10.1007/s00723-015-0684-1Scopus ID
2-s2.0-84938209697 (requires institutional sign-in at Scopus site) 6 CitationsAbstract
This study validated the use of small unilamellar vesicles (SUVs) made of 1-palmitoyl-2-oleoylphosphatidylcholine with 1 mol% spin label of 1-palmitoyl-2-(16-doxylstearoyl)phosphatidylcholine (16-PC) as an oxygen sensitive analyte to study cellular respiration. In the analyte the hydrocarbon environment surrounds the nitroxide moiety of 16-PC. This ensures high oxygen concentration and oxygen diffusion at the location of the nitroxide as well as isolation of the nitroxide moiety from cellular reductants and paramagnetic ions that might interfere with spin-label oximetry measurements. The saturation-recovery EPR approach was applied in the analysis since this approach is the most direct method to carry out oximetric studies. It was shown that this display (spin-lattice relaxation rate) is linear in oxygen partial pressure up to 100% air (159 mmHg). Experiments using a neuronal cell line in suspension were carried out at X-band for closed chamber geometry. Oxygen consumption rates showed a linear dependence on the number of cells. Other significant benefits of the analyte are: the fast effective rotational diffusion and slow translational diffusion of the spin-probe is favorable for the measurements, and there is no cross reactivity between oxygen and paramagnetic ions in the lipid bilayer.
Author List
Mainali L, Vasquez-Vivar J, Hyde JS, Subczynski WKAuthors
Witold K. Subczynski PhD Professor in the Biophysics department at Medical College of WisconsinJeannette M. Vasquez-Vivar PhD Professor in the Biophysics department at Medical College of Wisconsin
